Paving breaker steel



Aug. 18, 1959 H.' HARRISON E'rAL 2,900,178

PAVING BREAKER STEEL -Filed March 10, 1953 N 28 i e 28 V I I2 FIG 4 3o F/G 3 INVENTORS HENRY. HARRISON HENRY a HARRISON THEIR ATTORNEY United States Patent 2,900,178 PAVING BREAKER STEEL Henry Harrison and Henry C. Harrison, Port Washington, N.Y., assignors to Ingersoll-Rand Company, New York, N.Y., a corporation of New Jersey Application March 10, 1958, Serial No. 720,197

3 Claims. (Cl. 26233) ,This invention relates to tools for breaking concrete and the like, and more particularly to an improved type of percussively operated tool for this purpose.

It is the principal object of the present invention to provide a tool for breaking concrete and the like which is capable to be utilized for impact penetration, cutting and breaking, as well as for a wedging effect upon the penetrated material.

Another object of the present invention is to provide a percussively operated tool for breaking concrete and the like having an improved shape with which clearance is obtained for escape of the chips and dust in the hole being drilled.

A further object of the present invention is to provide a percussively operated tool which is capable of breaking concrete and the like more rapidly than herebefore practiced.

Another object of the present invention is to provide a percussively operated tool with a positive wedging action with no binding effect on the material to be broken.

Still another object of the present invention is to provide a percussively operated tool which is simple, efiicient, and highly resistant to wear.

These and other objects and advantages of this invention will more fully appear from the following description made in connection with the accompanying drawings in which:

Figure 1 is a front elevational view of a paving breaker steel constructed in accordance with the present invention,

Fig. 2. is a side elevational view of the paving breaker steel shown in Fig. 1,

Fig. 3 is a transverse sectional view of the paving breaker steel as taken on the line 33 of Fig. 1 and looking in the direction of the arrows, and

Fig. 4 is an end view of the tool shown in Fig. 1 and.

looking in the direction of the arrows.

Referring now more particularly to the drawing, the tool in accordance with the present invention includes an elongated body having at its forward or working end thereof a cutting portion 12 which is provided with a cutting edge 14. At the opposite end of the body 10, a shank 16, preferably of hexagonal cross section, is provided for engagement with the chuck (not shown) of a pneumatic hammer (not shown), and a collar 18 of conventional type may be provided at the intermediate portion of the tool.

Between the cutting portion 12 and the collar 18 an intermediate portion 20 is provided comprising a wedge portion 22 which extends from the cutting portion 12 towards the collar 18.

The wedge portion 22 comprises two pairs of opposed faces 24 and 26 of which the faces 26 converge towards the cutting portion 12 while the faces 24 are parallel side faces.

The cutting portion 12 comprises two pairs of opposed faces28 and 30 of which the faces 28 are side faces extending from the side faces 24 of the wedge portion and 2 ce I divergingtfrom the junction 32 between the wedge porcordance with the present invention, the parallel side faces 24 of the wedge portion 22 extend into the diverging side faces 28 of the cutting portion 12, while the converging faces 26 of the wedge portion 22 extend into the parallel faces 30 of the cutting portion 12.

The tool is preferably made of a single piece of alloy steel capable of being hardened throughout.

In operation, the tool is connected to a pneumatic hammer (not shown) and impacts are imparted to the tool in the usual manner.

The cutting portion 12 is driven into the material to be broken and penetrates therein producing a hole of a size at least as wide as the maximum width of the cut ting portion 12. With the feature of downwardly diverging side faces 28 and the maximum width of the cutting portion 12 exceeding the maximum width of the wedge portion 22, the cutting portion 12 provides a means of clearance for the escape of chips and dust in the hole being drilled and therewith assures rapid and uninterrupted operation of the tool.

As the cutting portion 12 penetrates the material to be broken it will be apparent that the material will be weakened in proportion of the depth of the hole being drilled. In view thereof, the length of the cutting portion 12 will be determined in accordance with the thickness of the material to be broken. After the cutting portion 12 has fully penetrated the material to be broken, a wedg ing action against the edges of the hole, obtained by the downwardly converging faces 26 of the wedge portion 22, will follow and the material will be subjected to lateral pressure tending to split the material. It will be clear, that, the greater the penetration of the tool into the material, the greater the wedging force of the wedge portion 22 will be to tend to split the material.

It is to be noted that, as the tool continues its operation, by reason of its structure, there will be no binding effect and the tool may be withdrawn at any time during operation.

It should be understood that the description and drawing herein are illustrative merely, and that various modifications and changes may be made in the structure disclosed without departing from the spirit of the invention.

We claim:

1. In a percussively operated tool for breaking concrete and the like, an elongated body comprising a shank at one end and a cutting portion at the other end, a cutting edge formed at the lower end of said cutting portion, and a wedge portion extending from said cutting portion towards the shank, said wedge portion having two pairs of opposed faces of which one pair converges towards the cutting portion and the other pair being substantially parallel side faces, said cutting portion having two pairs of opposing faces of which one pair being side faces extending from said parallel side faces of the wedge portion and diverging towards said cutting edge, the other pair of faces of said cutting portion extending parallelly from the wedge portion towards the cutting edge to prevent said tool from wedging in the concrete during initial penetration of the tool in such concrete.

2. In a percussively operated tool for breaking concrete and the like, an elongated body having a substantially pairs of opposed faces, one pair of opposed faces of each 1 of said portions converging towards the junction between the said portion, and one pair of said converging faces being positioned such that a longitudinal plane therethrough and normal thereto is angularly'disposed with respect to such a plane through the other oftsaid converging faces, and the faces of each pairvof the other of said pairs of opposed faces being substantially parallel.

3. The tool claimed in claim 2 in which the maximum 7 A w .r 2,900,178

References Cited in the file of patent width of the cutting portion exceeds the maximum width 2, 2 ,0

of the wedge portion of said tool.

UNITED STATES PATENTS Hengen May 19, 1896 Mowlds Mar. 7, 1916 Thomson Jan. 26, 1926 Hansen July 6, 1926 Neamond Feb. 24, 1953 Wyman Oct. 18, 1955 

